package com.botann.projects.utils;

/**
 * stock
 * RSASignature
 * Created by 刘山国 on 2019/4/19.
 * Copyright (c) 2017 伯坦科技. All rights reserved
 */
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

/**
 * RSA签名验签类
 */
public class RSASignature{

    /**
     * 签名算法
     */
    public static final String SIGN_ALGORITHMS = "SHA1WithRSA";

    public static String sign(String content, String privateKey) {
        return sign(content,privateKey,null);
    }

    /**
     * RSA签名
     * @param content 待签名数据
     * @param privateKey 商户私钥
     * @param encode 字符集编码
     * @return 签名值
     */
    public static String sign(String content, String privateKey, String encode) {
        try {
            PKCS8EncodedKeySpec priPKCS8    = new PKCS8EncodedKeySpec( Base64.decode(privateKey) );

            KeyFactory keyf                 = KeyFactory.getInstance("RSA");
            PrivateKey priKey               = keyf.generatePrivate(priPKCS8);

            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);

            signature.initSign(priKey);
            byte [] bytes = encode == null ? content.getBytes() : content.getBytes(encode);
            signature.update(bytes);

            byte[] signed = signature.sign();

            return Base64.encode(signed);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }



    public static boolean doCheck(String content, String sign, String publicKey) {
        return doCheck(content,sign,publicKey,null);
    }

    /**
     * RSA验签名检查
     * @param content 待签名数据
     * @param sign 签名值
     * @param publicKey 分配给开发商公钥
     * @param encode 字符集编码
     * @return 布尔值
     */
    public static boolean doCheck(String content, String sign, String publicKey,String encode) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            byte[] encodedKey = Base64.decode(publicKey);
            PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
            signature.initVerify(pubKey);
            byte [] bytes = encode == null ? content.getBytes() : content.getBytes(encode);
            signature.update(bytes);
            boolean bverify = signature.verify( Base64.decode(sign) );
            return bverify;
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }



}
